1. Field of the Invention
This invention relates to tube couplings which may be single or multiple tube couplings providing inline, elbow or T-couplings or tube closures.
2. Background Prior Art
Our “Speedfit” tube connector (U.S. Pat. No. 4,005,883 and others) has a coupling body with a throughway open at one end and a tapered cam surface in the open end to receive a collet for locking a tube in the coupling. The collet is comprised against the tube by a slight withdrawal of the tube and collet from the coupling body which locks the tube in the coupling body. The collet can be depressed into the body to release the tube.
Our “SuperfSeal” design (U.S. Pat. No. 4,637,636) has a separate sleeve screwed onto the open end of the coupling body in which the tapered cam is formed. By screwing the sleeve onto the coupling body, the gripping action of the collet on the tube is increased. Also, the collet becomes locked up in the coupling body and cannot be depressed to release the tube.
Our “Speedfit/Superseal” coupling (U.S. Pat. No. 6,056,326) comprises a coupling body having a throughway open at one end to receive an end portion of a tube and having an internal cam surface tapering towards the open end in which a collet is located for locking the tube in the coupling surface, and having step means to limit entry of the collet into the throughway, the coupling body having a main body the throughway of which receives the end of a tube and contains said step means to limit insertion of the collet and an end cap in screwthreaded engagement with the main body containing said open end to the throughway and the tapered cam surface, and indexing means between the end cap and main body to define different positions of rotational adjustment in the first of which a tube can be inserted and, by depressing the collet into the coupling body, released from the coupling body and in the second of which the collet is engaged with the step means to prevent the collect being depressed into the coupling body to release the tube. In the preferred arrangement the end cap has an internally threaded sleeve portion encircling and in screwthreaded engagement with an external thread on the main body.
In the latter construction, an “O” ring seal is provided in the throughway in the coupling body to engage and seal with the outer surface of the tube. The seal is spaced from the ends of the collet by a washer or sleeve. This arrangement provides small cavities between adjacent components in which liquids can penetrate and become trapped and difficult to remove by cleaning. Such entrapped liquids can deteriorate over a period of time and cause contamination in subsequent liquid flowing through the coupling.